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governator-providers

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package com.netflix.governator.providers;

import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;

/**
 * {@literal @}ProvidesWithAdvice is a Guice usage pattern whereby a method of a module can be 
 * annotated with {@literal @}ProvidesWithAdvice to return the initial version of an object and then
 * have {@literal @}Advises annotated methods that can modify the object.  All of this happens BEFORE
 * the final object is injected.  This functionality is useful for frameworks that wish to provide
 * a default implementation of a type but allow extensions and customizations by installing modules
 * with {@literal @}Advises annotated methods.
 * 
 * For example,
 *
 *  * {@literal @}ProvidesWithAdvice
 * List provideList() { return new ArrayList<>(Arrays.asList("a", "b", "c")); }
 *
 * {@literal @}Advises
 * UnaryOperator> addMoreToList() { return list -> list.add("d"); }
 * 
 *
 * will add "d" to the original ["a", "b", "c"].  When List<String> is finally injected it'll have
 * ["a", "b", "c", "d"].
 * 
 * Note that {@literal @}ProvideWithAdvice can be used with qualifiers such as {@literal @}Named 
 * with matching qualifiers added to the {@literal @}Advises methods.
 * 
 */
@Documented 
@Target(METHOD) 
@Retention(RUNTIME)
public @interface ProvidesWithAdvice {

}